1. Field of the Invention
This invention concerns disposable diapers, incontinent briefs, and the like having elastically contractible waistbands.
2. Background Art
Infants (and other incontinents) wear disposable diapers to receive and contain urine, feces, and other body fluids. Disposable diapers function both to contain the discharged materials and to isolate these materials from the body of the wearer and from the wearer's surroundings. Modern embodiments of disposable diapers frequently perform these tasks in a manner superior to that of traditional cloth diapers.
Disposable diapers normally comprise three elements: a liquid permeable topsheet designed to be placed next to the wearer's skin; a liquid impermeable backsheet which forms, in use, the outer surface of the diaper; and an absorbent element interposed between the topsheet and the backsheet.
The topsheet is frequently a hydrophobic non-woven fabric which is readily permeable to fluid. Its hydrophobicity tends to cause the surface in contact with the wearer's skin to be dry and protected from fluids absorbed within the absorbent element.
The absorbent element receives and retains fluids which pass through the topsheet. It normally comprises a batt of airlaid wood pulp fibers.
The backsheet functions to contain fluids within the absorbent element thereby protecting the wearer's outer garments and other surfaces from soiling by these fluids. Backsheets are commonly formed of fluid impermeable, vapor impermeable material such as polyethylene film.
Disposable diapers having many different basic designs are known to the art. For example, Duncan and Baker in U.S. Pat. No. Re. 26,152, issued Jan. 31, 1967, describe and claim a disposable diaper which has achieved wide acceptance and commercial success. Buell, in U.S. Pat. No. 3,860,003, issued Jan. 14, 1975, describes and claims another disposable diaper which, too, has achieved wide acceptance and commercial success. The diaper taught by Buell differs from that taught by Duncan and Baker in many respects, not the least of which is the provision in the Buell diaper of elasticized (or contractible) leg cuffs. Another embodiment of disposable diapers is described and claimed by Aziz and Blaney in European Patent Application No. 82200801.7, filed June 29, 1982. The Aziz and Blaney diaper also provides elasticized (or contractible) leg cuffs, but is of a somewhat different design than that described by Buell.
Mesek et al in U.S. Pat. No. 4,324,245, issued Apr. 13, 1982; Pieniak et al in U.S. Pat. No. 4,337,771, issued July 6, 1982; and Mesek et al in U.S. Pat. No. 4,352,355, issued Oct. 5, 1982 describe disposable diapers having elasticized cuffs and elasticized (or contractible) waistbands.
Strickland and Visscher in U.S. Pat. No. 4,253,461, issued on Mar. 3, 1981, describe and claim another form of disposable diaper sometimes referred to as an incontinent brief and intended to be worn by adults.
While the disposable diapers described above, particularly those described by Duncan and Baker, Buell, and Aziz and Blaney, function in exemplary manners, disposable diapers comprising fluid and vapor impermeable backsheets have sometimes been perceived as being somewhat hot and uncomfortable. Further, diapers provided with such impermeable backsheets are unable to self-dry as they otherwise would because evaporation of fluids from the absorbent element is precluded. To counteract this perception, and to permit self-drying, backsheets which are relatively impermeable to liquid but relatively permeable to vapor and which are known as breathable backsheets have been described. Breathable backsheets tend to provide a cooler garment and permit some measure of self-drying of the diaper while it is being worn. For example, Crowe, Jr. in U.S. Pat. No. 3,156,242, issued on Nov. 10, 1964, teaches the use of a microporous film as a breathable backsheet. Hartwell, in U.S. Pat. No. 3,881,489, issued on May 6, 1975, teaches a breathable backsheet comprising, in combination, two layers: a low-void volume perforated thermoplastic film and a porous high-void volume hydrophobic tissue. Sisson, in U.S. Pat. No. 3,989,867, issued on Nov. 2, 1976, teaches a breathable backsheet provided with tapered hollowed bosses which prevent the passage of liquid while allowing vapor to pass readily therethrough. Obenour, in U.S. Pat. No. 4,341,216, issued July 27, 1982, describes and claims a still different embodiment of a breathable backsheet.
The above cited ten patents and patent application are incorporated herein by reference.
While breathable backsheets do provide an improvement over the more common liquid and vapor impermeable backsheets, and while those described in the patents to Sisson, Hartwell and Obenour are of particular value, developments providing for more comfortable and more serviceable diapers have still been sought.